铜矿区含低浓度NH4+-N、Cu2+污水的处理

Treatment of wastewater containing NH4+-N and Cu2+ in copper mining area

  • 摘要: 针对铜矿区含低浓度NH4+-N、Cu2+污水的特征,采用吸附法+曝气生物滤池(BAF)联合工艺处理此类污水。研究了改性铜渣基陶粒对模拟污水中Cu2+的去除规律,考查了铜渣基陶粒填料的BAF对模拟污水吸附脱铜后液中NH4+-N的去除效果。结果表明:在Cu2+初始浓度为50 mg/L、溶液初始pH值约为5.00,陶粒添加量20 g/L,温度35 ℃,时间120 min的条件下,改性陶粒对模拟污水中Cu2+的吸附效果较佳,其平衡吸附量可达0.936 mg/g; 在陶粒添加量为40 g/L,温度35 ℃条件下,对含Cu2+,NH4+-N初始浓度分别为20、100 mg/L的模拟污水进行同步吸附处理时,改性陶粒对Cu2+的去除率达80%,污水中剩余Cu2+的浓度仅为4.0 mg/L,但对NH4+-N的去除效果不明显; 在水力停留时间HRT=6 h、碳氮比m(C/N)=4/1、pH=8.00左右、曝气量为1.2 L/min的较优工艺下,BAF对模拟污水脱铜后液中NH4+-N的去除率达96%;吸附法与BAF联合工艺可有效处理铜矿区含低浓度NH4+-N,Cu2+污水,处理后Cu2+,NH4+-N浓度达国家排放标准要求。

     

    Abstract: In view of the characteristics of wastewater sewage containing low-concentration NH4+-N and Cu2+ in copper mining areas, amethod combined adsorption with biological aerated filter (BAF) processes was applied to for this kind of sewage treatment. The adsorption and removal of Cu2+ in simulated sewage by modified copper slag-based ceramsite were explored. And the removal efficiency of BAF filled with the ceramsites on NH4+-N in simulated wastewater after copper removed by adsorption process was investigated under different operating conditions. The results showed that under the optimum conditions of the initial concentration of Cu2+ in sewage being 50 mg/L, the initial pH value about 5.00, the ceramsite addition of 20 g/L, the temperature of 35 ℃, and the adsorption time 120 min, the modified ceramsite had a good adsorption effect on Cu2+with the equilibrium adsorption capacity reaching about 0.936 mg/g.Under the conditions of the initial concentrations of Cu2+and NH4+-N in simulated wastewater 20 and 100 mg/L, respectively, adding content of ceramsite 40 g/L, temperature 35 ℃, the removal rate of Cu2+adsorbed by the modified ceramsite reached 80% with the rest Cu2+ concentration being only 4.0 mg/L, while the removal effect of the ceramsite on NH4+-N was not obvious. When the simulated wastewater was treated by BAF after Cu2+ in it was removed by the modified ceramsite, under the optimum conditions of hydraulic residence time HRT=6 h, carbon-nitrogen ratio m(C/N)=4/1, pH=8.00 and aeration rate of 1.2 L/min, the removal rate of NH4+-N reached 96%. The combined process of adsorption and biological aerated filter (BAF) technique could effectively treat the wastewater containing low concentration of NH4+-N and Cu2+ in copper mine area, and the rest concentrations of Cu2+ and NH4+-N in the wastewater both met the requirements of national emission standards.

     

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